This is true ^. My ex used that topical numbing crap they give pussies when she had her tattoo finished on her hip bone (it goes from her shoulder down) and it got real nasty looking. Plus, she said that it barely even managed the pain. Though you could argue that it was because she is a fucking skinny bitch and had her hip bones more pronounced.
Honestly, I just use my hydrocodone that I have for my shoulder. If I am getting work done, I just time it right when I need to take the hydro for pain management. Works well and no loopy side effects..... other than kidney failure.